Preparation of the antifouling microfiltration membranes from poly(N,N-dimethylacrylamide) grafted poly(vinylidene fluoride) (PVDF) powder

Abstract

Poly(vinylidene fluoride) (PVDF) powder is graft polymerized with N,N-dimethylacrylamide (DMAA) by a pre-irradiation induced graft polymerization technique. The existence of the graft chains in grafted PVDF (PVDF-g-PDMAA) powder has been proven by FT-IR spectroscopy and X-ray Photoelectron Spectroscopy (XPS) analysis. Then, the microfiltration (MF) membranes are prepared by isothermal immersion precipitation from PVDF-g-PDMAA powder in 1-methyl-2-pyrrolidone (NMP) solution from a water bath. The hydrophilicity of the MF membranes is determined by measuring the contact angles. The asymmetric morphology of the grafted membranes is studied by scanning electron microscopy (SEM), and water filtration properties are tested. The interaction between the membranes and proteins is studied by comparing the fluorescence microscopy images of these MF membranes cast from pristine PVDF and PVDF-g-PDMAA with a degree of grafting (DG) of 17.1% after surface fouling by Fluorescein Isothiocyanate (FITC)-conjugated Human Albumin solution. The antifouling property is determined by measuring the recovery percentage of pure water flux after the MF membranes have been fouled by bovine serum albumin (BSA) and lysozyme aqueous solution, separately. The results confirm that the existence of PDMAA graft chains improves the hydrophilicity and reduces protein adsorption of these MF membranes cast from PVDF-g-PDMAA powder.